Fast and accurate quality inspection of permanent magnets is increasingly important in development and production of many technological products, such as position sensors, electric motors and actuators, speakers and microphones, medical devices, automotive electronics etc. The quality of the end product is often directly influenced and largely dependent on the quality of permanent magnets in these products. Moreover, price volatility of rare earth materials, which are critical for making permanent magnets, force developers and manufacturers to use these precious materials in an efficient way, minimizing the amount of wasted magnet material, in other words, get the most performance out of the least amount of magnet material, meaning each magnet needs to conform to strict quality demands. Also from an economic point of view, quality control of permanent magnets is growing in importance.
A magnetic measurement system is known, also referred to as a magnetic field camera, which is an advanced magnet inspection technology for all kinds of permanent magnets, including uniaxial and multi pole magnets in various applications. The magnetic field camera technology is based on mapping the magnetic field distribution of a magnet using a plurality of magnetic field sensors.
In European patent application EP1720026, an example of such a magnetic field camera, also called a magnetic camera module, is described.
In European patent application EP2508906, an arrangement is described for characterizing magnetic systems based on an initialized set of input parameters of the magnetic system, the arrangement comprising:                means for measuring the magnetic field distribution, typically embodied as a magnetic camera module, and        means for determining an optimal expected magnetic field distribution of the magnetic system.        
Existing magnetic camera devices are able to measure the out-of-plane component or z-component of a magnetic field, with respect to the plane defined by the camera's sensing surface. The out-of-plane component or z-component of a magnetic field is thereby only determined along a predetermined two-dimensional surface.
There exists a need in industry to quickly and efficiently determine the out-of-plane component or z-component of such magnetic field in a three dimensional volume, i.e. for instance at different heights above a magnetic camera's main sensing surface.